Graphene, which is a two-dimensional sheet of sp2-bonded carbon atoms, has attracted tremendous attention in almost all scientific and technological fields. Because the shape, width, etc., of graphene determine the properties thereof, synthesis of structurally homogeneous graphene is one of the major objectives in this research field.
Polycyclic aromatic hydrocarbon (PAH) is expected to be a promising material for producing graphene, and there is a great potential demand for a simple and efficient method of synthesizing PAH derivatives. Transition-metal-catalyzed direct arylation of one or more C—H bonds of an aromatic ring is considered to be one of the simplest and most ideal methods of synthesizing PAH derivatives. From such a standpoint, direct arylation of C—H bonds of commercially available small PAHs, which can be performed by a simple method, is significantly useful for synthesizing large PAHs (Non-patent Literature 1 to 3). However, thus-far reported substrates applicable for direct arylation are mostly those having a heteroaromatic ring or a directing group, and there have been few reports concerning direct arylation of PAHs (Non-patent Literature 3).